| Upstream-Status: Pending |
| Signed-off-by: Gowtham Suresh Kumar <gowtham.sureshkumar@arm.com> |
| |
| From 2d975e5ec5df6f81d6c35fe927f72d49181142f8 Mon Sep 17 00:00:00 2001 |
| From: Julian Hall <julian.hall@arm.com> |
| Date: Tue, 19 Jul 2022 12:43:30 +0100 |
| Subject: [PATCH] Fix UEFI get_variable with small buffer |
| |
| The handling of the UEFI get_variable operation was incorrect when |
| a small or zero data length was specified by a requester. A zero |
| length data length is a legitimate way to discover the size of a |
| variable without actually retrieving its data. This change adds |
| test cases that reproduce the problem and a fix. |
| |
| Signed-off-by: Julian Hall <julian.hall@arm.com> |
| Change-Id: Iec087fbf9305746d1438888e871602ec0ce15824 |
| --- |
| .../backend/test/variable_store_tests.cpp | 60 ++++++++++++++++-- |
| .../backend/uefi_variable_store.c | 46 +++++++++++--- |
| .../client/cpp/smm_variable_client.cpp | 33 +++++----- |
| .../client/cpp/smm_variable_client.h | 8 ++- |
| .../provider/smm_variable_provider.c | 2 +- |
| .../service/smm_variable_service_tests.cpp | 62 +++++++++++++++++++ |
| 6 files changed, 179 insertions(+), 32 deletions(-) |
| |
| diff --git a/components/service/smm_variable/backend/test/variable_store_tests.cpp b/components/service/smm_variable/backend/test/variable_store_tests.cpp |
| index 235642e6..98faf761 100644 |
| --- a/components/service/smm_variable/backend/test/variable_store_tests.cpp |
| +++ b/components/service/smm_variable/backend/test/variable_store_tests.cpp |
| @@ -128,7 +128,8 @@ TEST_GROUP(UefiVariableStoreTests) |
| |
| efi_status_t get_variable( |
| const std::wstring &name, |
| - std::string &data) |
| + std::string &data, |
| + size_t data_len_clamp = VARIABLE_BUFFER_SIZE) |
| { |
| std::vector<int16_t> var_name = to_variable_name(name); |
| size_t name_size = var_name.size() * sizeof(int16_t); |
| @@ -144,21 +145,40 @@ TEST_GROUP(UefiVariableStoreTests) |
| access_variable->NameSize = name_size; |
| memcpy(access_variable->Name, var_name.data(), name_size); |
| |
| - access_variable->DataSize = 0; |
| + size_t max_data_len = (data_len_clamp == VARIABLE_BUFFER_SIZE) ? |
| + VARIABLE_BUFFER_SIZE - |
| + SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_DATA_OFFSET(access_variable) : |
| + data_len_clamp; |
| + |
| + access_variable->DataSize = max_data_len; |
| |
| efi_status_t status = uefi_variable_store_get_variable( |
| &m_uefi_variable_store, |
| access_variable, |
| - VARIABLE_BUFFER_SIZE - |
| - SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_DATA_OFFSET(access_variable), |
| + max_data_len, |
| &total_size); |
| |
| + data.clear(); |
| + |
| if (status == EFI_SUCCESS) { |
| |
| const char *data_start = (const char*)(msg_buffer + |
| SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_DATA_OFFSET(access_variable)); |
| |
| data = std::string(data_start, access_variable->DataSize); |
| + |
| + UNSIGNED_LONGLONGS_EQUAL( |
| + SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_TOTAL_SIZE(access_variable), |
| + total_size); |
| + } |
| + else if (status == EFI_BUFFER_TOO_SMALL) { |
| + |
| + /* String length set to reported variable length */ |
| + data.insert(0, access_variable->DataSize, '!'); |
| + |
| + UNSIGNED_LONGLONGS_EQUAL( |
| + SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_DATA_OFFSET(access_variable), |
| + total_size); |
| } |
| |
| return status; |
| @@ -336,6 +356,38 @@ TEST(UefiVariableStoreTests, persistentSetGet) |
| LONGS_EQUAL(0, input_data.compare(output_data)); |
| } |
| |
| +TEST(UefiVariableStoreTests, getWithSmallBuffer) |
| +{ |
| + efi_status_t status = EFI_SUCCESS; |
| + std::wstring var_name = L"test_variable"; |
| + std::string input_data = "quick brown fox"; |
| + std::string output_data; |
| + |
| + /* A get with a zero length buffer is a legitimate way to |
| + * discover the variable size. This test performs GetVariable |
| + * operations with various buffer small buffer sizes. */ |
| + status = set_variable(var_name, input_data, 0); |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_SUCCESS, status); |
| + |
| + /* First get the variable without a constrained buffer */ |
| + status = get_variable(var_name, output_data); |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_SUCCESS, status); |
| + |
| + /* Expect got variable data to be the same as the set value */ |
| + UNSIGNED_LONGLONGS_EQUAL(input_data.size(), output_data.size()); |
| + LONGS_EQUAL(0, input_data.compare(output_data)); |
| + |
| + /* Now try with a zero length buffer */ |
| + status = get_variable(var_name, output_data, 0); |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_BUFFER_TOO_SMALL, status); |
| + UNSIGNED_LONGLONGS_EQUAL(input_data.size(), output_data.size()); |
| + |
| + /* Try with a non-zero length but too small buffer */ |
| + status = get_variable(var_name, output_data, input_data.size() -1); |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_BUFFER_TOO_SMALL, status); |
| + UNSIGNED_LONGLONGS_EQUAL(input_data.size(), output_data.size()); |
| +} |
| + |
| TEST(UefiVariableStoreTests, removeVolatile) |
| { |
| efi_status_t status = EFI_SUCCESS; |
| diff --git a/components/service/smm_variable/backend/uefi_variable_store.c b/components/service/smm_variable/backend/uefi_variable_store.c |
| index e8771c21..90d648de 100644 |
| --- a/components/service/smm_variable/backend/uefi_variable_store.c |
| +++ b/components/service/smm_variable/backend/uefi_variable_store.c |
| @@ -1,5 +1,5 @@ |
| /* |
| - * Copyright (c) 2021, Arm Limited. All rights reserved. |
| + * Copyright (c) 2021-2022, Arm Limited. All rights reserved. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| * |
| @@ -294,7 +294,10 @@ efi_status_t uefi_variable_store_get_variable( |
| |
| status = load_variable_data(context, info, var, max_data_len); |
| var->Attributes = info->metadata.attributes; |
| - *total_length = SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_TOTAL_SIZE(var); |
| + |
| + *total_length = (status == EFI_SUCCESS) ? |
| + SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_TOTAL_SIZE(var) : |
| + SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_DATA_OFFSET(var); |
| } |
| } |
| |
| @@ -682,7 +685,6 @@ static efi_status_t load_variable_data( |
| { |
| EMSG("In func %s\n", __func__); |
| psa_status_t psa_status = PSA_SUCCESS; |
| - size_t data_len = 0; |
| uint8_t *data = (uint8_t*)var + |
| SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_DATA_OFFSET(var); |
| |
| @@ -692,17 +694,41 @@ static efi_status_t load_variable_data( |
| |
| if (delegate_store->storage_backend) { |
| |
| - psa_status = delegate_store->storage_backend->interface->get( |
| + struct psa_storage_info_t storage_info; |
| + |
| + psa_status = delegate_store->storage_backend->interface->get_info( |
| delegate_store->storage_backend->context, |
| context->owner_id, |
| info->metadata.uid, |
| - 0, |
| - max_data_len, |
| - data, |
| - &data_len); |
| - EMSG("In func %s get status is %d\n", __func__, psa_status); |
| + &storage_info); |
| + |
| + if (psa_status == PSA_SUCCESS) { |
| |
| - var->DataSize = data_len; |
| + size_t get_limit = (var->DataSize < max_data_len) ? |
| + var->DataSize : |
| + max_data_len; |
| + |
| + if (get_limit >= storage_info.size) { |
| + |
| + size_t got_len = 0; |
| + |
| + psa_status = delegate_store->storage_backend->interface->get( |
| + delegate_store->storage_backend->context, |
| + context->owner_id, |
| + info->metadata.uid, |
| + 0, |
| + max_data_len, |
| + data, |
| + &got_len); |
| + |
| + var->DataSize = got_len; |
| + } |
| + else { |
| + |
| + var->DataSize = storage_info.size; |
| + psa_status = PSA_ERROR_BUFFER_TOO_SMALL; |
| + } |
| + } |
| } |
| |
| return psa_to_efi_storage_status(psa_status); |
| diff --git a/components/service/smm_variable/client/cpp/smm_variable_client.cpp b/components/service/smm_variable/client/cpp/smm_variable_client.cpp |
| index 8438285b..b6b4ed90 100644 |
| --- a/components/service/smm_variable/client/cpp/smm_variable_client.cpp |
| +++ b/components/service/smm_variable/client/cpp/smm_variable_client.cpp |
| @@ -1,5 +1,5 @@ |
| /* |
| - * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved. |
| + * Copyright (c) 2021-2022, Arm Limited and Contributors. All rights reserved. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| @@ -122,21 +122,22 @@ efi_status_t smm_variable_client::get_variable( |
| guid, |
| name, |
| data, |
| - 0); |
| + 0, |
| + MAX_VAR_DATA_SIZE); |
| } |
| |
| efi_status_t smm_variable_client::get_variable( |
| const EFI_GUID &guid, |
| const std::wstring &name, |
| std::string &data, |
| - size_t override_name_size) |
| + size_t override_name_size, |
| + size_t max_data_size) |
| { |
| efi_status_t efi_status = EFI_NOT_READY; |
| |
| std::vector<int16_t> var_name = to_variable_name(name); |
| size_t name_size = var_name.size() * sizeof(int16_t); |
| - size_t data_size = 0; |
| - size_t req_len = SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_SIZE(name_size, data_size); |
| + size_t req_len = SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_SIZE(name_size, 0); |
| |
| rpc_call_handle call_handle; |
| uint8_t *req_buf; |
| @@ -154,7 +155,7 @@ efi_status_t smm_variable_client::get_variable( |
| |
| access_var->Guid = guid; |
| access_var->NameSize = name_size; |
| - access_var->DataSize = data_size; |
| + access_var->DataSize = max_data_size; |
| |
| memcpy(access_var->Name, var_name.data(), name_size); |
| |
| @@ -168,26 +169,28 @@ efi_status_t smm_variable_client::get_variable( |
| |
| efi_status = opstatus; |
| |
| - if (efi_status == EFI_SUCCESS) { |
| - |
| - efi_status = EFI_PROTOCOL_ERROR; |
| + if (resp_len >= SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_NAME_OFFSET) { |
| |
| - if (resp_len >= SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_NAME_OFFSET) { |
| + access_var = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE*)resp_buf; |
| + size_t data_size = access_var->DataSize; |
| |
| - access_var = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE*)resp_buf; |
| + if (resp_len >= |
| + SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_TOTAL_SIZE(access_var)) { |
| |
| - if (resp_len >= |
| - SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_TOTAL_SIZE(access_var)) { |
| + if (efi_status == EFI_SUCCESS) { |
| |
| - data_size = access_var->DataSize; |
| const char *data_start = (const char*) |
| &resp_buf[ |
| SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE_DATA_OFFSET(access_var)]; |
| |
| data.assign(data_start, data_size); |
| - efi_status = EFI_SUCCESS; |
| } |
| } |
| + else if (efi_status == EFI_BUFFER_TOO_SMALL) { |
| + |
| + data.clear(); |
| + data.insert(0, data_size, '!'); |
| + } |
| } |
| } |
| else { |
| diff --git a/components/service/smm_variable/client/cpp/smm_variable_client.h b/components/service/smm_variable/client/cpp/smm_variable_client.h |
| index c7973916..3d2371a8 100644 |
| --- a/components/service/smm_variable/client/cpp/smm_variable_client.h |
| +++ b/components/service/smm_variable/client/cpp/smm_variable_client.h |
| @@ -1,5 +1,5 @@ |
| /* |
| - * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved. |
| + * Copyright (c) 2021-2022, Arm Limited and Contributors. All rights reserved. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| @@ -56,7 +56,8 @@ public: |
| const EFI_GUID &guid, |
| const std::wstring &name, |
| std::string &data, |
| - size_t override_name_size); |
| + size_t override_name_size, |
| + size_t max_data_size = MAX_VAR_DATA_SIZE); |
| |
| /* Remove a variable */ |
| efi_status_t remove_variable( |
| @@ -113,6 +114,9 @@ public: |
| |
| |
| private: |
| + |
| + static const size_t MAX_VAR_DATA_SIZE = 65536; |
| + |
| efi_status_t rpc_to_efi_status() const; |
| |
| static std::vector<int16_t> to_variable_name(const std::wstring &string); |
| diff --git a/components/service/smm_variable/provider/smm_variable_provider.c b/components/service/smm_variable/provider/smm_variable_provider.c |
| index 1f362c17..95c4fdc9 100644 |
| --- a/components/service/smm_variable/provider/smm_variable_provider.c |
| +++ b/components/service/smm_variable/provider/smm_variable_provider.c |
| @@ -165,7 +165,7 @@ static rpc_status_t get_variable_handler(void *context, struct call_req *req) |
| } |
| else { |
| |
| - /* Reponse buffer not big enough */ |
| + /* Response buffer not big enough */ |
| efi_status = EFI_BAD_BUFFER_SIZE; |
| } |
| } |
| diff --git a/components/service/smm_variable/test/service/smm_variable_service_tests.cpp b/components/service/smm_variable/test/service/smm_variable_service_tests.cpp |
| index 38c08ebe..989a3e63 100644 |
| --- a/components/service/smm_variable/test/service/smm_variable_service_tests.cpp |
| +++ b/components/service/smm_variable/test/service/smm_variable_service_tests.cpp |
| @@ -284,6 +284,68 @@ TEST(SmmVariableServiceTests, setAndGetNv) |
| UNSIGNED_LONGLONGS_EQUAL(EFI_SUCCESS, efi_status); |
| } |
| |
| +TEST(SmmVariableServiceTests, getVarSize) |
| +{ |
| + efi_status_t efi_status = EFI_SUCCESS; |
| + std::wstring var_name = L"test_variable"; |
| + std::string set_data = "UEFI variable data string"; |
| + std::string get_data; |
| + |
| + efi_status = m_client->set_variable( |
| + m_common_guid, |
| + var_name, |
| + set_data, |
| + 0); |
| + |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_SUCCESS, efi_status); |
| + |
| + /* Get with the data size set to zero. This is the standard way |
| + * to discover the variable size. */ |
| + efi_status = m_client->get_variable( |
| + m_common_guid, |
| + var_name, |
| + get_data, |
| + 0, 0); |
| + |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_BUFFER_TOO_SMALL, efi_status); |
| + UNSIGNED_LONGS_EQUAL(set_data.size(), get_data.size()); |
| + |
| + /* Expect remove to be permitted */ |
| + efi_status = m_client->remove_variable(m_common_guid, var_name); |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_SUCCESS, efi_status); |
| +} |
| + |
| +TEST(SmmVariableServiceTests, getVarSizeNv) |
| +{ |
| + efi_status_t efi_status = EFI_SUCCESS; |
| + std::wstring var_name = L"test_variable"; |
| + std::string set_data = "UEFI variable data string"; |
| + std::string get_data; |
| + |
| + efi_status = m_client->set_variable( |
| + m_common_guid, |
| + var_name, |
| + set_data, |
| + EFI_VARIABLE_NON_VOLATILE); |
| + |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_SUCCESS, efi_status); |
| + |
| + /* Get with the data size set to zero. This is the standard way |
| + * to discover the variable size. */ |
| + efi_status = m_client->get_variable( |
| + m_common_guid, |
| + var_name, |
| + get_data, |
| + 0, 0); |
| + |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_BUFFER_TOO_SMALL, efi_status); |
| + UNSIGNED_LONGS_EQUAL(set_data.size(), get_data.size()); |
| + |
| + /* Expect remove to be permitted */ |
| + efi_status = m_client->remove_variable(m_common_guid, var_name); |
| + UNSIGNED_LONGLONGS_EQUAL(EFI_SUCCESS, efi_status); |
| +} |
| + |
| TEST(SmmVariableServiceTests, enumerateStoreContents) |
| { |
| efi_status_t efi_status = EFI_SUCCESS; |
| -- |
| 2.17.1 |
| |